11, 2000 -- Two images made by NASA's Chandra X-ray Observatory,
one in October 1999, the other in January 2000, show for the
first time the full impact of the actual blast wave from Supernova
1987A (SN1987A). The observations are the first time that X-rays
from a shock wave have been imaged at such an early stage of
a supernova explosion.
NASA's Chandra X-ray Observatory
images a young supernova blast wave.
Right: This Chandra X-ray image of SN 1987A made in January 2000 shows an expanding shell of hot gas produced by the supernova explosion.
Recent observations of SN 1987A with the Hubble Space Telescope revealed gradually brightening hot spots from a ring of matter ejected by the star thousands of years before it exploded. Chandra's X-ray images show the cause for this brightening ring. A shock wave is smashing into portions of the ring at a speed of 10 million miles per hour (4,500 kilometers per second). The gas behind the shock wave has a temperature of about ten million degrees Celsius, and is visible only with an X-ray telescope.
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The X-ray observations appear to confirm the general outlines of a model developed by team member Richard McCray of the University of Colorado, Boulder, and others, which holds that a shock wave has been moving out ahead of the debris expelled by the explosion. As this shock wave collides with material outside the ring, it heats it to millions of degrees. "We are witnessing the birth of a supernova remnant for the first time," McCray said.
Left: This two-frame animation is an excerpt from a more detailed online movie illustrating the events following the supernova 1987A outburst. The blue ring is previously observed material ejected from the star thousands of years ago. The expanding orange and yellow shell is multimillion degree, X-ray emitting gas produced by the explosion. Portions of the blue ring light up when struck by the X-ray shell. QuickTime animations: High Res (3228090 Bytes) | Low Res (1035129 Bytes)
The Chandra images clearly show the previously unseen, shock-heated matter just inside the optical ring. Comparison with observations made with Chandra in October and January, and with Hubble in February 2000, show that the X-ray emission peaks close to the newly discovered optical hot spots, and indicate that the wave is beginning to hit the ring.
In the next few years, the shock wave will light up still more material in the ring, and an inward moving, or reverse, shock wave will heat the material ejected in the explosion itself. "The supernova is digging up its own past," said McCray.
Right: Chandra/Hubble composite image of SN1987A. This Chandra X-ray image of SN 1987A made in January 2000 shows an expanding shell of hot gas produced by the supernova explosion. The colors represent different intensities of X-ray emission, with white being the brightest. Also shown are the contours from a Hubble Space Telescope optical image taken on 2 February 2000. Scale: The optical ring is 1.2 x 1.6 arcsec, corresponding to 1.0 x 1.3 light years.
The observations were made on October 6, 1999, using the Advanced CCD Imaging Spectrometer (ACIS) and the High Energy Transmission Grating, and again on January 17, 2000, using ACIS. Other members of the team were Eli Michael of the University of Colorado; Dr. Una Hwang, Dr. Steven Holt and Dr. Rob Petre of NASA's Goddard Space Flight Center in Greenbelt, MD; and Professors Gordon Garmire and John Nousek of Pennsylvania State University. The results will be published in an upcoming issue of the Astrophysical Journal.
The ACIS instrument was built for NASA by the Massachusetts Institute of Technology, Cambridge, and Pennsylvania State University. The High Energy Transmission Grating was built by the Massachusetts Institute of Technology. NASA's Marshall Space Flight Center in Huntsville, AL, manages the Chandra program. TRW, Inc., Redondo Beach, CA, is the prime contractor for the spacecraft. The Smithsonian's Chandra X-ray Center controls science and flight operations from Cambridge, MA.Web Links
X-Rays - Another Form of Light - the basics of X-rays from the Chandra home page at Harvard
X-ray Astronomy Field Guide: Supernovae
and Supernova Remnants
- from the Harvard Center for Astrophysics
Chandra home page -from Harvard
Chandra News -from NASA
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Press Release 00-149|
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